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876dd978b8
The original version didn't properly account for the base register being modified before the final jump, so caused miscompilations in Chromium and LLVM. I've fixed this and tested with an LLVM self-host (I don't have the means to build & test Chromium). The general idea remains the same: in pathological cases jump tables can be too far away from the instructions referencing them (like other constants) so they need to be movable. Should fix PR23627. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238680 91177308-0d34-0410-b5e6-96231b3b80d8
53 lines
1.5 KiB
LLVM
53 lines
1.5 KiB
LLVM
; RUN: llc -mtriple=thumbv7s-apple-ios8.0 -o - %s | FileCheck %s
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declare void @foo(double)
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declare i32 @llvm.arm.space(i32, i32)
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; The constpool entry used to call @foo should be directly between where we want
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; the tbb and its table. Fortunately, the flow is simple enough that we can
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; eliminate the entry calculation (ADD) and use the ADR as the base.
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;
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; I'm hoping this won't be fragile, but if it does break the most likely fix is
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; adjusting the @llvm.arm.space call slightly. If this happens too many times
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; the test should probably be removed.
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define i32 @test_jumptable_not_adjacent(i1 %tst, i32 %sw, i32 %l) {
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; CHECK-LABEL: test_jumptable_not_adjacent:
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; CHECK: vldr {{d[0-9]+}}, [[DBL_CONST:LCPI[0-9]+_[0-9]+]]
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; [...]
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; CHECK: adr.w r[[BASE:[0-9]+]], [[JUMP_TABLE:LJTI[0-9]+_[0-9]+]]
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; CHECK-NOT: r[[BASE]]
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; CHECK: [[TBB_KEY:LCPI[0-9]+_[0-9]+]]:
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; CHECK-NEXT: tbb [r[[BASE]], {{r[0-9]+}}]
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; CHECK: [[DBL_CONST]]:
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; CHECK: .long
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; CHECK: .long
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; CHECK: [[JUMP_TABLE]]:
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; CHECK: .byte (LBB{{[0-9]+}}_{{[0-9]+}}-([[TBB_KEY]]+4)
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br label %complex
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complex:
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call void @foo(double 12345.0)
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call i32 @llvm.arm.space(i32 970, i32 undef)
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switch i32 %sw, label %second [ i32 0, label %other
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i32 1, label %third
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i32 2, label %end
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i32 3, label %other ]
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second:
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ret i32 43
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third:
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ret i32 0
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other:
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call void @bar()
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unreachable
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end:
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ret i32 42
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}
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declare void @bar()
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